Inverting liner pressurized tank

ABSTRACT

This disclosure describes a tank for holding water or other liquid under a selected range of pressure. It comprises a tank with a top opening and means to close and seal the top, with conduit means penetrating the top for the entry and discharge of liquid from the tank. The tank is lined with an impervious flexible cylindrical liner which is closed at the bottom and open at the top and is fastened by sealing over the top opening of the tank. Air or other gas is injected into the tank below the inverting liner so that the liquid is maintained at a pressure equal to that of the gas below the liner. The liner is of larger diameter than the tank, and is held in intimate contact with the tank by the internal pressure of the liquid inside the liner when in the extended position and by the gas pressure when the liner is in the inverted position. In one version a condensible gas such as Freon, of a selected composition is injected into the tank below the level of the liner instead of air or other noncondensible gas. Freon, being a gas condensible at ambient temperatures, can provide a pressure which is substantially constant depending on the temperature, and can vary in volume in accordance with the space provided below the water.

United States Patent [1 1 Lamkin 1 1 INVERTING LINER PRESSURIZED TANK[75] lnventor; James E. Lamkin, Tulsa, Okla.

[73] Assignees. Lee Roy Denham, Tulsa; Jack L.

Spradling, Bixby. both of. Okla part interest to each [22] Filed: Feb.26, 1973 [21] Appl No: 335,830

1158.296 11/1964 Cornelius i i l i A ZZZ/386.5 3,225,967 12/1965Hcmgartnerw 222/95 X $592,360 7/1971 Aleck 222/95 PrimaryExaminer-Robert B. Reeves Assistant Examiner-Larry H, Martin [57]ABSTRACT This disclosure describes a tank for holding water or 1 Apr. s,1975 other liquid under a selected range of pressure. It comprises atank with a top opening and means to close and seal the top, withconduit meanspenetrating the top for the entry and discharge of liquidfrom the tank. The tank is lined with an impervious flexible cylindricalliner which is closed at the bottom and open at the top and is fastenedby sealing over the top opening of the tank. Air or other gas isinjected into the tank below the inverting liner so that the liquid ismaintained at a pressure equal to that of the gas below the liner. Theliner is of larger diameter than the tank and is held in intimatecontact with the tank by the internal pressure of the liquid inside theliner when in the extended position and by the gas pressure when theliner is in the inverted position. In one version a condensible gas suchas Freon, of a selected composition is injected into the tank below thelevel of the liner instead of air or other noncondensible gas. Freon,being a gas condensible at ambient temperatures, can provide a pressurewhich is substantially constant depending on the temperature. and canvary in volume in accordance with the space provided below the water.

12 Claims, 5 Drawing Figures BACKGROUND OF THE INVENTION DESCRIPTION OFTHE PREFERRED EMBODIMENT Referring now to the drawings and in particularto This invention lies in the field of pressurized water or FIG. 1 thereis shown a pressurized water tank of this other liquid storage tanks.More particularly it is concerned with pressurized water tanks whichinclude a flexible impervious liner inside of the water tank so that thewater is maintained in contact with the liner, and out of contact withthe shell of the tank. The water is also separated from the gas.

An improved embodiment of this invention utilizes a gas condensible atambient temperatures instead of a noncondensible gas, so that there is alesser range in pressure as the gas is compressed and therefore thewater can occupy an increasingly large part of the internal volume ofthe tank.

In the prior art there has been shown pressurized water storage tanks inwhich the water is separated from a pressurized gas by a flexiblediaphragm, or by containment of the water in a loose bag resting onbottom. In the use of air, for example, or other type of permanent gas,as the volume of water increases on one side of the diaphragm the volumeof gas on the other side decreases and the pressure in the gas can riserapidly providing a restriction to the further increase in volume ofwater. Thus, when the tank is almost empty of water the permanent gasprovides an unsatisfactorily low pressure, when the tank is almostfilled with water the permanent gas provides too high a pressure.

SUMMARY OF THE INVENTION This invention varies from the prior art in theuse of a liner diaphragm of thin flexible material which is larger indiameter than the tank, so that while under internal pressure it isconstricted by the tank walls to retain the liner diaphragm in place,preventing collapse, and allowing a controlled inverting action. Thus,it is possible to place the tank in any position with water locatedeither at the top or the bottom of the tank. The use of a thin membraneis economical as compared to one thick enough to be self-supporting.

This invention also varies from the prior art in the use of acondensible gas, such as Freon, in place ofthe permanent gas, so that asthe tank becomes filled with water and the gas space becomes smaller andsmaller, as the pressure in the gas increases, it will condense andstill maintain a suitable back pressure against the water. Thus it ispossible to utilize a far greater fraction of the volume of the tank forwater, when a condensible gas is used, than when a permanent gas isused. Thus a smaller size of tank can store an equal volume of waterwhen used with a condensible gas than can be stored in a much largertank when pressurized with a permanent gas.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 illustrates one embodiment ofthis invention.

FIG. 2 illustrates the use of the pressurized tank of this invention.

FIG. 3 illustrates an improved version of the water storage tank.

FIG. 4 shows a detail of FIG. 3.

FIG. 5 shows a characteristic of Freon as one of the many condensiblegases that might be used in the apparatus of this invention.

invention indicated generally by the numeral 10. This is a closed,sealed cylindrical tank having a cylindrical side wall 20 and top 18 andbottom 22. There is a large opening at the top which as shown in FIG. 4can be sealed with a cover plate 34 through which a pipe passes so thatliquid can be introduced into and withdrawn from the inside of the tank.

The tank is normally buried in the earth and may rest upon a foundation26 for example. Cylindrical tubular means 40 are provided to protect thetop of the tank from the caving of earth. This tubular portion 40 may becovered with a plate 42 at the surface 12 of the earth 14. A valve means32 is provided through which the tank can be pressurized with acondensible gas prior to its burial inside of the earth.

In FIG. 2 is shown one way in which this pressurized tank can be used.It shows the tank submerged in the earth. A cover plate 34 has a pipeconnected to the tee 38 which passes through the cover plate 34 into thetank. A horizontal line 36 leads to a pump 44 with motor 46 which drawswater in through a vertical pipe 48 in accordance with the arrow 50 orit may draw water in from a horizontal pipe 52 leading to a distantsource of water, the water moving in the direction of the arrow 54. Thepump pulling in the water from means 48 or 52 discharges it horizontallythrough line 36 into the tank from which it can be drawn back to the tee38 and go in either direction of the pipes 36 or 37 to serve users ofthe water.

FIG. 3 shows in more detail the construction of the tank in crosssection. There is a flexible tubular liner 26 which is of a diameterslightly greater than the inner diameter of the tank. It is closed offon the bottom by a transverse sheet 27.

By reference to FIG. 4 it is seen that the liner 26 snugly fits theupper portion of the tank and passes through the opening 62 and isspread out as a gasket 64 to seal the cover plate 34, which is held downby means of bolts 66.

There is an inner wall 58 which is closely spaced 60 from thecylindrical wall of the tank 10. This inner wall is welded to the top ofthe tank at point 61. The annular space 60 is connected with the spacebelow the diaphragm or liner, indicated by numeral 28, which is thespace into which the Freon is injected through valve 32. The purpose ofthe inner wall and the space 60 is to provide a large area of contactbetween the Freon inside the tank, and the earth outside the tank, sothat the Freon will have a good heat transfer path to derive heat fromthe earth in order to evaporate, and increase its volume as the pressuredrops, and vice versa, to give off heat to the earth as the pressure isincreased and its volume decreases.

The cylindrical wall 26 of the liner is of a diameter which isapproximately 10 percent greater than the inner diameter of the tank orof the inner wall 58. This greater diameter is provided so that when thetank is filled with water there is an internal pressure forcing theliner against the outer wall. The liner will be compressed and thereforewill have a tendency to cling to the wall, and not collapse, as thepressure is reduced. This feature permits using a much thinner linerthan would otherwise be necessary if the liner was to be supported byits own thickness and stiffness. The liners that can be used in thisinvention can be as thin as 0.030 inches up to 0.060 inches for tanksfour to seven feet in diameter, and propertionately less for tanks oflesser diameter, with a consequent saving in material of the liner. Theliner can be made of any rubber-like material that is elastic andcompressible. A preferred material is acrylonitrile rubber.

The liner is installed in the tank in a fully inverted position and thetank is then charged by inserting air or other gas below the liner. Oncethe tank is charged with gas the liner can only be extended by liquidforced into the liner. This is because a liquid is required to lubricateand separate the surfaces of the inverted liner which are in intimatecontact due to the inverting of the liner and the compression of theliner within the tank walls.

In FIG. 4 is shown in some detail the pipes 36 and 37 leading to the tee38 with an entry pipe 70 going through the cover plate 34 to a terminalarrangement 72. This is an inverted feature attached to the bottomsurface of the top plate, with a plurality of very narrow slots throughwhich water can flow into and out of the tank. By making these slotsnarrow the pressure of the gas against the bottom of the liner cannotforce it into the openings 70 and therefore there is no danger ofperforating the liner, which would be the case if these openings were onthe bottom face of the cup 72 for example, and particularly if they wereof substantial width.

While this invention can be used with various types of condensible gasesfor a number of reasons it has been found that Freon is a desirable gasfor this purpose. In particular, mixtures of Freon l2 and Freon 21provide a satisfactory characteristic of pressure, at the temperaturerange that might be encountered in the earth at the depth of burial ofthe tank. In FIG. 5 there is shown a characteristic diagram of themixture of Freon l2 and Freon 21. The horizontal axis gives the Mo]percent Freon 12 in the mixture of Freon l2 and Freon 21. The pressureis shown on the ordinate. Examining the curve 76 labelled liquid, it isseen that if a pressure of 70 pounds per square is desired, a horizontalline 80 is drawn from the ordinate at point 84 corresponding to 70 psito the liquid line, and then vertically as line 82 down through tobottom line at point 86. This indicates a Mol percent of Freon 12 ofapproximately 47 percent to obtain a mixture which would provide apressure of 70 psi when all of the mixture is condensed and 58 psi whenall the mixture is vaporized, at a temperature of approximately 74 F.

Similar diagrams can be drawn for other gas mixtures such as Freon 12with Freon 22, for example. These gases are well known in industry andare available on the market. Their pressure versus temperaturecharacteristics are well known. For the curves shown in FIG. 5 therelationship of pressure to M0] percent for the liquid and the gas aregiven more precisely by the follow ing equations:

Where P and P are the corresponding vapor and liquid pressures, and theM01 percent is of Freon 12 in a mixture with Freon 21.

These relationships are well known, and a mixture can be easily designedfor use in the apparatus of this invention covering any pressure andtemperature range desired.

In FIG. 3 the inverted portion of the liner 27 is shown of lesserdiameter than the portion 26. This is only for purposes of illustration,and in actual operation the gas pressure inside the inverted portionwill force the walls outwardly into intimate contact with the portion 26of the liner. The water or other liquid inside the liner will providelubrication for the portions sliding against each other.

While the invention has been described with a certain degree ofparticularity it is manifest that many changes may be made in thedetails of construction and the arrangement of components. It isunderstood that the invention is not to be limited to the specificembodiments set forth herein by way of exemplifying the invention, butthe invention is to be limited only by the scope of the attached claimor claims, including the full range of equivalency to which each elementor step thereof is entitled.

What is claimed:

1. An inverting liner pressurized liquid tank comprising:

a. a pressure tight tank open at the top and closure means to close saidopening, an inner wall inside said tank sealed to said tank at its topedge and providing an annular space between said inner wall and saidtank;

b. a tubular flexible, compressible, impermeable inverting liner closedoff with a transverse wall at the bottom, and open at the top, adaptedwhile subjected to internal pressure to snugly fit against the insidesurface of said tank and said inner wall, the open top of said linersealed around said top opening of said tank;

c. conduit means through said closure means for admitting a flow ofwater into and out of said liner; and

d. means to inject a condensible gas, of a selected pressure versustemperature relation, to provide a selected pressure range over aselected tempera ture range, into said tank below the bottom of saidliner.

2. The tank as in claim 1 in which said condensible gas if Freon.

3. The tank as in claim 2 in which said Freon is Freon 12 intermixedwith Freon 21.

4. The tank as in claim 2 in which said Freon is Freon l2 intermixedwith Freon 22.

5. The tank as in claim 1 in which the diameter of said liner isapproximately l0 percent greater than the internal diameter of said tankand said wall whereby under internal pressure said liner will becompressed and will be supported from collapsing.

6. The tank as in claim I in which said liner is of a thickness in therange of 0.030 inches to 0.060 inches.

7. The tank as in claim 1 in which said liner is made of rubber likematerial.

8. The tank as in claim 1 in which said liner is made of acrylonitrilerubber.

9. An inverting liner pressurized liquid tank comprising:

a. a pressure tight tank open at the top and closure means to close saidopening, an inner wall inside said tank sealed to said tank at its topedge and providing an annular space between said inner wall and saidtank;

b. a tubular, flexible, compressible, impermeable inverting liner closedoff with a transverse wall at the bottom, and open at the top, thediameter of said liner larger in diameter than said tank, and adaptedwhile subjected to internal pressure to snugly fit against the insidesurface of said tank and said inner wall, the open top of said linersealed around said top opening of said tank;

c. conduit means through said closure means for admitting a flow ofliquid into and out of said liner; and

d. means to inject a selected gas, of a selected pressure versustemperature relation, to provide a selected pressure range over aselected temperature range, into said tank below the bottom of saidliner.

10. The tank as in claim 9 in which the diameter of said liner isapproximately 10 percent greater than the internal diameter of said tankand said wall, whereby under internal pressure said liner will becompressed and will be supported from collapsing.

I]. The tank as in claim 9 in which said selected gas is anoncondensible gas.

12. The tank as in claim 9 in which said selected gas is a mixture ofselected proportion of two compatible condensible gases each having adifferent pressure versus temperature relation such that the binarymixture of the selected components will have the desired pressure versustemperature relation.

t i i

1. An inverting liner pressurized liquid tank comprising: a. a pressure tight tank open at the top and closure means to close said opening, an inner wall inside said tank sealed to said tank at its top edge and providing an annular space between said inner wall and said tank; b. a tubular flexible, compressible, impermeable inverting liner closed off with a transverse wall at the bottom, and open at the top, adapted while subjected to internal pressure to snugly fit against the inside surface of said tank and said inner wall, the open top of said liner sealed around said top opening of said tank; c. conduit means through said closure means for admitting a flow of water into and out of said liner; and d. means to inject a condensible gas, of a selected pressure versus temperature relation, to provide a selected pressure range over a selected temperature range, into said tank below the bottom of said liner.
 2. The tank as in claim 1 in which said condensible gas if Freon.
 3. The tank as in claim 2 in which said Freon is Freon 12 intermixed with Freon
 21. 4. The tank as in claim 2 in which said Freon is Freon 12 intermixed with Freon
 22. 5. The tank as in claim 1 in which the diameter of said liner is approximately 10 percent greater than the internal diameter of said tank and said wall whereby under internal pressure said liner will be compressed and will be supported from collapsing.
 6. The tank as in claim 1 in which said liner is of a thickness in the range of 0.030 inches to 0.060 inches.
 7. The tank as in claim 1 in which said liner is made of rubber like material.
 8. The tank as in claim 1 in which said liner is made of acrylonitrile rubber.
 9. An inverting liner pressurized liquid tank comprising: a. a pressure tight tank open at the top and closure means to close said opening, an inner wall inside said tank sealed to said tank at its top edge and providing an annular space between said inner wall and said tank; b. a tubular, flexible, compressible, impermeable inverting liner closed off with a transverse wall at the bottom, and open at the top, the diameter of said liner larger in diameter than said tank, and adapted while subjected to internal pressure to snugly fit against the inside surface of said tank and said inner wall, the open top of said liner sealed around said top opening of said tank; c. conduit means through said closure means for admitting a flow of liquid into and out of said liner; and d. means to inject a selected gas, of a selected pressure versus temperature relation, to provide a selected pressure range over a selected temperature range, into said tank below the bottom of said liner.
 10. The tank as in claim 9 in which the diameter of said liner is approximately 10 percent greater than the internal diameter of said tank and said wall, whereby under internal pressure said liner will be compressed and will be supported from collapsing.
 11. The tank as in claim 9 in which said selected gas is a noncondensible gas.
 12. The tank as in claim 9 in which said selected gas is a mixture of selected proportion of two compatible condensible gases each having a different pressure versus temperature relation such that the binary mixture of the selected components will have the desired pressure versus temperature relation. 